Brain disease risk on Elan drug rises

THE INCIDENCE of a rare brain disease in multiple sclerosis patients taking Elan’s Tysabri has risen again, with seven new cases in the past month.

This compares with four cases in the previous month, and 11 over the previous quarter.

A total of 42 confirmed cases of progressive multifocal leukoencephalopathy (PML) were reported by March 10th. Of these, just over one in five – nine cases – has proven fatal. Patients outside the US continue to prove more vulnerable to PML, with 24 cases to date in the EU, 15 in the US and three elsewhere.

The numbers succumbing to PML earlier in treatment is also rising. The latest figures, released to medical practitioners by Biogen – partner to Elan in the Tysabri project – show the incidence of PML in patients taking Tysabri for more than 18 months has risen to 1.18 per 1,000, compared to 0.89 per 1,000 at the end of 2009.

The figures for those on medication for two years or more has risen sharply over the same period to 1.42 per 1,000, compared to 1.02 per 1,000 at the end of December. The companies have been expecting an increase in the incidence of PML as more patients pass through the two-year prescribing barrier.

Goodbody analyst Dr Ian Hunter said yesterday “we have to await the reaction of regulators as the incidence in patients on the drug over 18 months increases”.

Late last year regulators in the US and Europe recommended a change in wording of prescribing instructions to patients to indicate that the longer they stay on the drug, the greater the risk of PML.

In the latest data, the rate of PML exceeds one in 1,000 in patients taking the treatment for 12 months – at 1.03 per 1,000.

Shares in Elan and Biogen were down slightly on the news.